Roadside bomb injures 20 policemen in the restive north of Egypt's Sinai

FILE - In this Monday, Oct. 27, 2014 file photo, Egyptian President Abdel-Fattah el-Sissi waits for a meeting with U.S. Treasury Secretary Jack Lew at the presidential palace in Cairo, Egypt. El-Sissi endorsed the law defining voting districts in the country of more than 50 million voters, his spokesman said Thursday, July 9, 2015, removing the last hurdle for a date to be set for the much delayed parliamentary elections. (AP Photo/Hassan Ammar, Pool, File)
(The Associated Press)

FILE - In this April 1, 2011 photo, activist Ahmed Douma, left, chants slogans as activist Khaled ElSayed, right, supports him, during a march to Tahrir Square demanding the prosecution of members of former President Hosni Mubarak's regime in Cairo, Egypt. On Thursday, the wife and the lawyer of a prominent secular activist, Khaled ElSayed, said he was detained at Cairo airport before boarding a plane to Qatar. (AP Photo/Sarah Carr, File)
(The Associated Press)

AL-ARISH, Egypt – Security officials say 20 policemen were injured when their bus and armored personnel carrier were hit by a roadside bomb in the turbulent north of Egypt's Sinai Peninsula.

The officials say the bus carried policemen in civilian clothes as they left the town of al-Arish at the start of their leave. The armored carrier was their escort.

Most of the 20 injured policemen were lightly wounded, according to the officials, who spoke on condition of anonymity because they were not authorized to speak to the media.

Thursday's bombing came about a week after a coordinated attack by Islamic militants in northern Sinai killed 17 army soldiers, according to the Egyptian military. Officials in several branches of the security and military services say scores were killed in the July 1 attack.